1. Field of the Invention
The present invention relates to a rotation rate sensor.
2. Description of Related Art
A conventional micromechanical rotation rate sensor usually includes a mass situated in a mounting support so as to be displaceable, which mass is able to be driven into an oscillatory motion with respect to the mounting support. If a rotary body on which the micromechanical rotation rate sensor is affixed executes a rotary motion which is not parallel to the oscillatory motion, a Coriolis force is imparted to the mass driven into the oscillatory motion, by which the displaceable mass is additionally deflected. Via a sensor device, which includes a capacitor, for example, this additional deflection of the displaced mass can be detected and evaluated with regard to a variable describing the rotary motion of the rotatable body, for instance. Such a variable is a rate of rotation of the rotary motion of the rotatable body, for instance.
Published U.S. patent applications U.S. 2005/0081633 A1, U.S. 2006/0219006 A1, and U.S. 2005/0082252 A1 describe rotation rate sensors whose displaceable masses can be driven into an oscillatory motion about a first axis of rotation. In this case a Coriolis force can impart an additional rotary motion to the oscillating mass in a plane of oscillation about a second axis of rotation that is aligned perpendicular to the first axis of rotation, and thereby cause shifting/tilting of the displaced mass out of the plane of oscillation.
However, the rotation rate sensors of published U.S. patent applications US 2005/0081633 A1, US 2006/0219006 A1 and US 2005/0082252 A1 have the disadvantage that only a portion of the mass driven into an oscillatory motion about the first axis of rotation is deflected by the Coriolis force about the second axis of rotation. In these types of rotation rate sensors, the Coriolis force therefore induces a relatively weak signal whose evaluation with regard to information representing the rotary motion of the rotatable body is relatively imprecise and often contains errors. In addition, the detection and the evaluation of the shifting/tilting of the oscillating mass out of its plane of oscillation due to the Coriolis force is relatively complex.